The proposed study will investigate changes in the social networks and burden of primary caregivers to elderly relatives with Alzheimer's disease (AD) over a two-year period following the initial diagnosis of dementia. In particular, the study will examine the ways in which changes in the structure and function of social networks effect caregiver burden. Structured face-to- face interviews with 400 caregivers will be conducted at three points following the relative's diagnosis: within three weeks after diagnosis, one year after the initial interview, and two years after the initial interview. The respondents will be drawn from three major medical centers. This study will examine the ways in which differences in the structure of caregivers' social networks affect the degree of support provided. Further, we will explore whether certain types of support and interaction lead to a greater reduction in the stress and burden experienced by caregivers. More general literature on social support and stress suggest that the buffering effects of social interaction and support vary substantially, depending on the characteristics of the relationship between the individual and his or her associates. Therefore, we will examine how changes in interaction with and support from various network members over time differentially affect caregiver burden. The proposed study will provide a substantial methodological improvement over most previous investigations of caregivers. First, the study will employ a longitudinal design, in contrast to almost all other studies of caregivers, which have been cross-sectional. Second, the study will utilize precise measures of social network structure and function, in contrast to the more general measures of social support and family relations used in previous studies of caregivers. Third, multiple measures of caregiver burden will be employed, including measures of both physical and psychological well-being and subjective stress experienced in providing care.